1. Field of the Invention
The invention relates to a method of transporting and transferring the assembled equipment of a deck for the fixed ocean platform, the method involving assembling the equipment at a yard on land, transferring the assembled equipment to means of transport towed to the site, and transferring the assembled equipment to the deck of the platform to be equipped.
2. The Prior Art
The infrastructure of an ocean platform is usually constructed on land in one or more parts, which parts are towed to the site, assembled and then submerged by controlling their buoyancy. The deck is subsequently equipped with the installations corresponding to the intended use of the platform. These installations are produced from modules of standard weights and dimensions, which are assembled together in situ. In seas with normal climatic conditions, the modules are lifted and put in place by means of conventional barge cranes and semi-submersible appliances. On the other hand, the use of these same appliances in seas with difficult climatic conditions does not allow a sufficient level of efficiency to be achieved during the very short periods in which the atmospheric conditions make it possible to work under adequate safety conditions. To reduce the time necessary for lifting the elements and putting them in place and consequently lessen the climatic risks as well as the handling costs and other direct expenses, attempts have been made to increase the lifting capacity of the barge cranes and semi-submersibles, but a limit has been reached, and beyond this the appliances are so costly that they can only be profitable if they are used at a relatively high daily work rate.
Unfortunately, the depreciation of these appliances is only acceptable in a few projects.
There are also serious disadvantages arising from the methods used; thus, the risks inherent in any lifting work at sea increase in proportion to the weight lifted, and there are also the risks involved in transferring a load from a floating appliance to a fixed structure.
Even so, the time necessary for installing the equipment and for testing and accepting it is still not reduced thereby.
The installation work requires a large number of people who have to cope with difficult living conditions heightened by the climatic conditions.
A solution to these problems has been found for some platforms, particularly platforms with a weighted base and self-elevating platforms, this solution involving carrying out the complete installation of the deck and acceptance of the equipment at the construction yard and towing to the site the assembly consisting of the platform and the installed deck.
This method of construction limits the possibilities of use of the platform to those intended initially, and it is not possible, for example, to convert a drilling platform into a production platform in a simple way, since a large part of the installations has to be removed and replaced.